Elevator



C. B. COLLINS ELEVAT OR Filed Dec. 16, 1936 Nov. 1, 1938.

F IG. 4.

iNVENTFR:

@NAMES B. mums Mmmm" Patented Nov. 1, 1938 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to improvements in elevators and more particularly to pneumatic or fluid pressure elevators.

Among the objects is to provide an elevator comprising tubes telescoped within each other and adapted to raise safely and dependably both animate and inanimate objects.

Another object is to gradually retard each of the tubes as it nears the end of its operative movements.

Another object is to enable the upward movement of the elevator to be initiated smoothly.

Another object is to provide an elevator which is simple and relatively inexpensive in construction and permanently reliable in operation.

Other objects and advantages appear as this description progresses.

In this specication and the accompanying drawing, the invention is disclosed in its preferred form. It is to be understood, however, that it is not limited to this form because it may be embodied in other forms within the spirit of the invention as defined in the claims following the description.

In the one sheet of drawings:

Fig. 1 is a front elevation of an elevator constructed in accordance with this invention. The elevator is shown in extended position.

Fig. 2 is an enlarged vertical section of the upper portion of the elevator taken along the line II-II in Fig. 1.

Fig. 3 is a similar section taken along the line III--III in Fig. 1 showing the lower portion of the same in collapsed position.

Fig` 4 is a vertical section. taken along the line IV-IV in Figt 3.

In detail the structure illustrated in the drawing, referring more particularly to Fig. 3, comprises the base i which may be bolted to any suitable support such as a vehicle. The base has the annular internally threaded flange 2 which has the lower end of the tube 3 screwed thereinto.

A plurality of tubes 4, 5 of progressively smaller diameter are telescoped within the outer tube 3. Two telescoped tubes are illustrated in the accompanying drawing. However, a larger number of tubes may be employed as desired, Within the purview of the invention,

The innermost tube 5 has the bracket 5 fixed on, and sealing its upper end. A suitable goods platform may be mounted upon this bracket.

The lower ends of the tubes 3 and 4 are closed by the plugs 6, 'l which have the radial iianges 8, 9 slidably engaging the interiors of the tubes 3 and 4, respectively. The sealing cups iD, il are mounted beneath the plugs 6 and 'l by the rings i2, i3 and the screws I4, l5. The lips of these cups operatively engage the adjacent interior surfaces of the tubes 3, 4 to prevent the 5 upward escape of air therepast between the telescoped tubes.

The annular guides l and il are threaded in the upper ends of the tubes 3, 4 and are slidably engaged by the telescoped tubes 4, 5. The seal- 10 ing cups i8, composed of flexible material such leather, are fixed underneath the guides IG,

il and engage the exterior surface of the tubes fl, 5. These cups prevent the upward escape of air past the guides IE, Il. 15

The anges 8, 9 cooperate with the guides i6,

il to conne the tubes 4, 5 to vertical movement and enable the structure to withstand lateral thrusts.

The rings I9, 2U are welded or otherwise se- 20 cured to the sides of the tubes 4, 5 slightly above the flanges 8, 9 and have the leather sealing cups 2l, 22 xed thereupon. The lips of these cups operatively engage the outer tubes 3, 4 and prevent the escape of air downward past the rings 25 i9, 2D. Thus there is a quantity of air impounded between the cups lil-22, see Fig. 2, on the upward movement of the elevator. This air serves as a retarding cushion as will be later described. 30

The hollow valve stem 23 has its lower end screwed into the center of the base l. The plugs 6, .l have the openings 24, 25 therethrough to pass the stem E3. The openings 24, 25 are a close sliding fit over the stem 23 so as to minimize the 35 iiow of air therepast. The stem has the tapered head 26 with the orice 2l therethrough.

The base l has the passages 28, 29 therein which communicate with the interior of the stem E3. The passage 2li is closed by the stop cock 40 3D which discharges into the atmosphere. The valve 3l is screwed into the end of the passage and has the hose 32 connected thereto which leads to a suitable source of compressed air. The passage has the restriction 33 therein. 45

The hollow Valve 34 is a sliding fit within the stem Z3. It has the orice 35 through its upper end and the smaller ports 36 and 3l through its side. The holes 38 and 39 are adapted to register with the ports 36 and 3l and are located im- 50 mediately below the plugs 6 and l respectively when the hoist is in collapsed position as in Fig.

3. The setscrew 4i) in the stern 23 engages the groove 4| to hold the valve 34 against rotation. The spring 42 expands between the head 25 of 55 the stern and the top of the valve 34. It urges the valve into depressed position as in Fig. 3 with the ports 36, 31 out of registry with the holes 38, 39.

The springs 43 and 44 are interposed between the base I and the cap B and between the cap 6 and the cap 1, respectively. These springs yieldingly limit the downward movement of the tubes 4 and 5. The upward movement of the tubes 4 and 5 is limited by the pins 45 and 46. These pins are fixed in the rings I9 and 20 and project upwardly through holes provided in the sealing cup structure 2| and 22 and are arranged to abut the annular guides I6 and I1 at the end of the operative upward movement of the tubes 4 and 5.

In one use, the invention operates substantially as follows: Assuming the elevator to be in collapsed condition, a quantity of freight is loaded on to the goods platform (not shown) mounted on the bracket 5. The goods on the platform may then be raised to the desired level, such as the top of the stack of goods and unloaded.

Opening the Valve 3| permits compressed air from the hose 32 to flow into the passage 29 at a rate predetermined by the restriction 33. The compressed air passes from the passage 29, through the valve 34, the orifice 35, the orifice 21, into the interior of the tube 5. The oriiice 35 is slightly smaller than the orice 21. The air thus flows from the stem 23 through the orice 21 as fast as it can be supplied by the smaller orifice 35. The back pressure due to the orifice 21 will thus be negligible. A pressure diierential may thus be built up on opposite sides of the restriction at 35. The valve 34 is raised by this pressure differential and by lfriction incidental to the velocity of the air flowing therethrough until its movement is checked by the screw 40 engaging the end of the groove 4|. The ports 36, 31 then register with the holes 38, 39 permitting compressed air to flow underneath the plugs 6 and 1. The relatively small space beneath these plugs results in a high air pressure being quickly built up. The tubes 4 and 5 then simultaneously commence moving upward with respect to each other and with respect to the outer tube 3.

When the plugs 6 and 1 pass beyond the end of the stem 23, compressed air owng through the orice 21 and the ports 36 and 31 maintains equal pressures in the tube 4 and the tube 5. The two tubes thus continue to rise at equal rates.

There is a quantity of air impounded between the rings I9, 20 and the guides I6, I1 outside the tubes 4 and 5 respectively. As the tubes 4 and 5 ascend in unison this entrapped air is compressed and exerts a progressively increasing retarding force against the resting tubes. The hoist rises at moderate speed until it nears the end of its movement. The pressure of the entrapped air rises and brings the tubes to a gradual stop obviating shock as the air slowly leaks past the cups I8 and 2 I, 22.

The ends of the pins 45, 56 come into engagement with the guides I6 and I1 positively limiting the travel of the tubes. The structure is arranged so that the flanges 8 and 9 corne to rest a short distance below the guides I6 and I1 so as to render the hoist laterally stable when raised. The valve 3| is closed when the movement of the tubes ceases.

The platform is lowered by opening the valve 30. The compressed air within the tubes. then flows downward through the orifice 21`, into the stem 23, and through the passage 28 and out the valve 30 into the atmosphere. The decrease in pressure within the tubes 4, 5 allows them to descend under their own weight and that of any goods on the platform above. As the rings I9, 2U move away from the guides i6, Il, air flows from the atmosphere past the cups I3 into the space between the rings and guides.

The rate of descent will vary with the weight of the goods on the platform. To prevent too rapid descent when the platform is heavily loaded, the valve 30 can be only partially opened. This restricts the discharge of air and retards the descent of the tubes 4 and 5.

Near the end of the downward travel of the tubes, the plugs 6 and 1 slide over the stem 23. The valve 24 is urged by the expansion of the spring 42 into depressed position as in Fig. 3 with the ports 3G, 31 out of registry with the ports 38, 3S. The air underneath the plugs 6, 1 is thiis trapped and can escape only by slow leakage through the slight clearance provided between the stem 23 and the openings and 25. The final portion of the downward movement of the hoist is thus retarded and cushioned by the necessary compression of the beneath the plugs 6, 1. The tubes 4, 5 finally come to rest when the plugs 6, '.1' engage the springs 43, M.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

l. An elevator comprising a base; a tube ixed on said base; a plurality of telescoped tubes telescoping within said fixed tube and having plugs in their lower ends with openings therethrough; a value stem fixed on said base and projecting upwardly therefrom; means for admitting and withdrawing iluid pressure from said tubes through said valve stein to raise and lower said tubes relative to each other; said valve stem being adapted to close the openings in said plugs When said tubes approach the terminus of their downward movement; said valve stem having ports through its side to admit fluid pressure beneath each of said plugs to initiate the upward movement of said tubes; and means for closing said ports during the downward movement of said tubes.

2. An elevator comprising a base; a tube fixed on said base; a plurality of telescoped tubes tele scoping within said fixed tube and having plugs in their lower ends with openings therethrough; a valve stem xed on said base and projecting upwardly therefrom and having an orifice in the top thereof; means for admitting and withdrawing fluid pressure from said tubes through said orifice in said valve stern to raise and lower said tubes relative to each other; said valve stem being adapted to enter and substantially close the openings in said plugs when said tubes approach the terminus of their downward movement; said valve stem having lateral ports therein to admit uid pressure beneath each of said pings to initiate the upward movement of said tubes, a hollow valve within said valve stein adapted normally to close said lateral ports in said stem and arranged to open said ports when said valve is displaced by the passage of iiuid pressure through said stem and orice therein into said telescoping tube.

3. An elevator comprising a base; a tube xed on said base; a plurality of telescoped tubes telescoping within said fixed tube and having plugs in their lower ends with openings therethrough; a valve stem xed on said base in registry with said openings and projecting upwardly therefrom, and having an orifice in the top thereof;

means for admitting and withdrawing iiuid pressure from said tubes through said orce in said valve stem to raise and lower said tubes relative to each other; said valve stern being adapted to enter and substantially close the openings in said plugs when said tubes approach the terminus of their downward movement; said valve stem having ports through its side to admit uid pressure beneath each of said plugs to initiate the upward movement of said tubes; a hollow Valve within said stem having ports therethrough adapted to register with the ports in the side of said stem; resilient means urging said valve downwardly into a position with its ports out of registery with the ports in the side of said stem; said valve being adapted to be raised against the tension of said spring by the passage of uid through said stem into said tubes so as to bring the ports therein into registry with the ports in the side of said stem.

CHARLES B. COLLINS. 

